Need less significant digits returned in ArcGIS REST Services

ArcGIS REST Services: Taming Those Pesky Decimal Places (and Why You Should)

ArcGIS REST Services are fantastic, right? They’re the backbone of so many geospatial workflows, giving us access to GIS data and functionality over the web. But let’s be honest, sometimes they can be a bit… verbose. I’m talking about the way they spit out numerical data, especially coordinates and attribute values, with more decimal places than you can shake a stick at. We’re talking way more precision than you actually need.

So, what’s the big deal? Well, think about it. All those extra digits add up. You might see an elevation of “189.9” show up as “189.9000000001”. Doesn’t seem like much, does it? But multiply that by thousands of features, and suddenly you’re dealing with bloated data, sluggish performance, and a general headache. I remember one project where we were pulling in building footprints, and the coordinate data was just insane. The file sizes were huge, and the map took forever to load. It was a real wake-up call!

That’s why reigning in those significant digits is so important. Here’s why you should care:

• Speed Boost: Smaller data = faster transfers. This is crucial, especially if you’re building web apps or dealing with mobile users. Nobody wants to wait around for data to load.
• Readability Rocks: Data that’s easy to understand is just plain better. Fewer digits mean less squinting and head-scratching.
• Save Some Space: Okay, maybe you won’t become a millionaire by saving a few bytes per feature. But over time, it can definitely make a difference in storage costs, especially with massive datasets.

So, how do you actually do it? Don’t worry, it’s not rocket science. Here are a few tricks I’ve picked up over the years:

A few things to keep in mind:

• XY Resolution: This setting influences the precision of your coordinates. Keep it in mind when designing your geodatabase.
• Coordinate System Considerations: The coordinate system of your data and your service both play a role in the final precision.
• JSON Formatting: Be Careful: Using f=pjson is great for debugging, but don’t use it in production. It can slow things down.

A Word of Caution:

Don’t go overboard! You don’t want to lose important information by chopping off too many digits. Make sure you’re still accurate enough for your needs. And remember, while client-side formatting can make things look better, it doesn’t actually reduce the amount of data being transferred.

The Bottom Line

Reducing significant digits in your ArcGIS REST Services is a simple way to boost performance, improve readability, and save a bit of space. By using these tips and tricks, you can make your geospatial workflows smoother and more efficient. So go forth and conquer those pesky decimal places! Your users (and your servers) will thank you.